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use std::ops::{Index, IndexMut};
struct Foo {
x: isize,
y: isize,
}
impl<'a> Index<&'a String> for Foo {
type Output = isize;
fn index(&self, z: &String) -> &isize {
if *z == "x" {
&self.x
} else {
&self.y
}
}
}
impl<'a> IndexMut<&'a String> for Foo {
fn index_mut(&mut self, z: &String) -> &mut isize {
if *z == "x" {
&mut self.x
} else {
&mut self.y
}
}
}
struct Bar {
x: isize,
}
impl Index<isize> for Bar {
type Output = isize;
fn index<'a>(&'a self, z: isize) -> &'a isize {
&self.x
}
}
fn main() {
let mut f = Foo {
x: 1,
y: 2,
};
let mut s = "hello".to_string();
let rs = &mut s;
println!("{}", f[&s]);
//~^ ERROR cannot borrow `s` as immutable because it is also borrowed as mutable
f[&s] = 10;
//~^ ERROR cannot borrow `s` as immutable because it is also borrowed as mutable
let s = Bar {
x: 1,
};
s[2] = 20;
//~^ ERROR cannot assign to data in an index of `Bar`
drop(rs);
}
|
